Cosmological Radiative Transfer Simulations

The epoch of reionization, a phase transition that occurred in the Universe, is a combination of several non-linear events. In an effort to understand this transition and its subsequent effects, we are utilizing large scale radiative cosmological simulations. Our current focus is to add helium to simulations through ATON - a post processing radiative transfer code. To optimally study this, we have undertaken a multi-frequency approach and are using smaller simulation boxes to constrain the number of frequency bins required. We have validated the code through astrophysical tests with known analytical solutions. Addition of helium have opened up venues to study different observables such as the mean free path, photon distribution, helium fractions while allowing us to understand the interplay between helium and hydrogen. We are also planning to change the source spectrum of the halos to incorporate the effect of quasars. The long term aim is to study reionization epoch galaxies and the physical properties of the Intergalactic Medium with radiative transfer simulations for late-end reionization histories that match Lyman-alpha forest data.